Do not issue preflight for crossorigin media resource loads.

content/renderer/media/buffered_resource_loader.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/buffered_resource_loader.h"
 
 #include "base/bits.h"
 #include "base/callback_helpers.h"
 #include "base/format_macros.h"
 #include "base/metrics/histogram.h"
@@ skipping 170 matching lines @@
   if (test_loader_) {
     loader = test_loader_.Pass();
   } else {
     WebURLLoaderOptions options;
     if (cors_mode_ == kUnspecified) {
       options.allowCredentials = true;
       options.crossOriginRequestPolicy =
           WebURLLoaderOptions::CrossOriginRequestPolicyAllow;
     } else {
       options.exposeAllResponseHeaders = true;
+      // The author header set is empty, no preflight should go ahead.
+      options.preflightPolicy = WebURLLoaderOptions::PreventPreflight;
       options.crossOriginRequestPolicy =
           WebURLLoaderOptions::CrossOriginRequestPolicyUseAccessControl;
       if (cors_mode_ == kUseCredentials)
         options.allowCredentials = true;
     }
     loader.reset(frame->createAssociatedURLLoader(options));
   }
 
   // Start the resource loading.
   loader->loadAsynchronously(request, this);
@@ skipping 594 matching lines @@
 
 void BufferedResourceLoader::Log() {
   media_log_->AddEvent(
       media_log_->CreateBufferedExtentsChangedEvent(
           offset_ - buffer_.backward_bytes(),
           offset_,
           offset_ + buffer_.forward_bytes()));
 }
 
 }  // namespace content